This invention relates to domestic ovens and to a related cooking technique. The invention applies particularly to countertop electric ovens.
There are many electric countertop ovens, including toaster ovens and convection ovens, available on the market today for domestic uses. Almost every oven is claimed to be multi-functional, including functions of baking, broiling, baking and broiling, and/or toasting. However, the final quality of a baked product can be dependent upon not only the cooking mode but also the position of the product in an oven and the nature as well as the physical dimensions of the product. Many ovens have multiple slots at different levels for alternately receiving a shelf or a rack, thereby providing adjustability in the vertical position of the shelf or rack. The shelf or rack can be manually raised or lowered before a cooking procedure so that a food article is subjected to appropriate thermal treatment on both upper and lower surfaces.
It is often more desirable to have an adjustable shelf for supporting a metal pan (baking pan, roasting pan, grill pan, etc.) on which a food product is placed, wherein the shelf is continuously adjustable to any vertical position during a coking process. When on-line height adjustment is not necessary during a cooking cycle, the shelf can be adjusted to an optimal height before the oven power is switched on. When a faster rate of heat transfer to a lower surface of a food item is required only at the beginning of a cooking cycle, the shelf can first be positioned closer to the bottom of an oven and subsequently raised to a higher position.
Most conventional dometic ovens have two sets of heating elements disposed in opposition to one another, for instance, at the top and the bottom of an oven chamber. In order to develop necessary crust and surface browning on the bottom layer of a food product, it is important to have enhanced heat transfer to the bottom layer especially when the food product is placed on a non-perforated metal pan. When multiple slices of white bread are placed on a non-perforated bread pan and toasted in a countertop electric oven, for example, the bottom side of the multiple slices remains wet and white while the upper side turns brown and crispy. This difference in browning is due to the fact that the water vaporization rate at the lower surface of the bread is much lower than that of the upper surface.
Another typical example is the use of a countertop oven for re-heating of leftovers such as pizza slices. Without enhanced heat transfer from the lower surface, the surface could be soggy as the upper surface quickly turns brown when the pizza slices are placed on a non-perforated metal pan. Adjusting the shelf, metal pan and the food product to the lowest possible position in an oven would improve but would not solve the problem.